Hydraulic motor and control system therefor



May 25, 1965 E. GERBER HYDRAULIC MOTOR AND CONTROL SYSTEM THEREFOR Filed June 22, 1962 3 Sheets-Sheet l May 25,1965 EGERBR ,3,185,557

HYDRAULIC MOTOR AND CONTROL SYSTEM THEREFOR Filed June 22, 1952 5 sheets-sheet 2 May 25, 1965 E. GERBER 3,185,557

` HYDRAULIC MOTOR AND CONTROL SYSTEM THEREFOR l Filed June 22, 1962 s sheetsfsheet s Eri ` desired speed.

United States Patent O 3,185,557 HYDRAULIC MOTUR AND CONTROL p SYSTEM THEREFOR Ernest Gerber, Box 223, Coronation, Alberta, Canada Filed June 22, 1962, Ser. No. 204,542 Claims. (01460-53) My invention relates to new and useful improvements in hydraulic motors, particularly hydraulic motors adapted to be incorporated `upon. tractors andthe like and driven by a hydraulic pump which in turn is driven from a conventional source of power such as an internal be obtained as theraverage engineiis most efficient at one given rpm. i f

Attempts have been made to incorporate such engines with hydraulicipumps which in` turn `drive hydraulic motors connected tothe drive wheels of the` vehicles, but these are `expensive and relatively ineicient due `to the diiliculty in controlling the load and speed factors. This is normally done by varying thesupply of hydraulic which is relatively expensive.

` i I have overcome these dlsadvantages by providing a constant delivery pump driven by A`a"c`onventional source of power, speed variations being obtained by an inclined thrust plate `within the hydraulic motor against which a` rotating cylinder `and piston assembly bears, it merely being necessary to lengthen or shorten the veffective stroke of the individual pistons to control-thespeed of the tinal drive. i i' The principal object and essence of my invention is` `fluid and this in turn requires a variable velocity pump i FIGURE 6 is a section of FIGURE Patented May 25, 1965 ice device of the character herewithin described which is relatively simple in construction, economical in manufacture, and otherwise well suited to the purpose for which it is designed. l

With the foregoing objects in view, and such other objects and advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, my invention consists essentially in the arrangement and construction of parts all as here inafter more particularly described, reference being had to the accompanying drawings in which:

FIGURE 1 is a top plan view partially sectioned of my hydraulic motor. l

FIGURE 2 is a section of FIGURE 1 taken substantially along the line 2-2 thereof.

FIGURE 3 is a section of FIGURE 1 taken along the line 393.

FIGURE 4 is a` further section of FIGURE l taken along the line 4-4 thereof. p

FIGURE 5 is 1a fragmentary perspective view joef the distributor per se. p

2 taken along the line 6-6 thereof.

FIGURE 7 is a section of FIGURE 2 taken along the FIGURE 8 is a View of the motor reduced in scale 'to the remaining figures, showing the hydraulic drive circuit per se.

FIGURE 9 is a schematic view showing two of the indicate elusive in which numeral 10 illustrates a substantially therefore to provide an hydraulic motor and control syrsp tem therefor which utilizes a constant delivery type pum-p `driven by a conventionalwsource of power.'

Another object of my invention is to provide a device of the character herewithin `described which is particularly adaptable for use in tractors and theflikeinasmuch as it isfdesirable to provide an hydraulic motor for each rear wheel thereof. p l

Another object of my invention is to provide a device of the character herewithin described which, if desired, is easily adaptable to four wheel drive or, which can be incorporated with conventional rear axle construct-ions.

A yet further object of my invention is to provide a` device of the character herewithin described whichincorporates various valves and control piston and cylinder assemblies thereby giving the tollowingjadvantages. 1

(a) A simple braking system to either rear ,wheel is provided which may be operated independently or together to permit fast turns or emergency stops.

(b) If the source ofpowerf fails, the hydraulic system i `is locked immediately therefore preventing loss of control.

(c) A speed control lever `operating through a power assisted valve assembly is provided thereby maintaining the inclinedrplates in the desired" position thus giving the (d) Linkage means is incorporated with the inclined plate operating mechanism sc that when the speed control lever is closed .down to the lowermost position, a byapass valve opens thusV `by-passing the hydraulic iluid from the hydraulic motor to a circulating system, which not only obviates the necessity of shutting down the source of power but also ymaintains the hydraulic pressure within the motors thus acting as a parking brake.

Yet another object of my invention is to providea :cylindrical casing having end plates V11 and 12 secured tjo the anged ends 13 of the casing by means of bolts `14, sealing gaskets l(not illustrated) being incorporated between the end plates and the ends of the casing in order to prevent yoil leakage.

Situated within the casing is a cylinder and piston assembly collectively designated 15, said yassembly comprising a substantially cylindrical block 16whaving ,a plurality of cylinder bores 17 formed therein and situated radially as clearly shown in FIGURE 4.

Extending from the end 18 of the block 16 is a concentrically located drilling 19 Within which is situated -one end 20` of .a drive shaft 21, said drive shaft being keyed to the block `16 by means of key 22. The drive shaft 21 extends through a .bearing bushing 22 formed within the end plate 12 and the portion 23 .of the drive shaft extending beyond the hydraulic motor may be op eratively connected to the drive wheel of the vehicle (not illustrated).

Ywith apertures 28 communicating with each of the cylin- -ders 17 and conduits 29 are secured to the cylinder .head over each of the apertures 28, said conduits extend- Aing or inclining inwardly and being connected by the other ends thereof to a bearing sleeve 30 extending concentrically from the aforementioned cylinder head 24. This bearing sleeve is provided with a bearing surface 31 also apertured to communicate with each of the con- ,duits 29 and it should be observed that the bearing surface 31 is provided with a closed inner end 32 which acts as a thrust block as will hereinafter be described.

Extending inwardly from the end plate 11 ofthe casing is a bearing boss 33 over which is engageable the aforementioned bearing sleeve and surface 30, 31, oil `seal 34 being provided adjacent the inner surface 35 of the end plate 11 to prevent oil leakage therepast.

The bearing boss 33 is provided with vertically situa-ted distributor channels 36 and 36A upon each side of the bearing boss and intermediate the ends thereof, thus leaving a web 37 therebetween as clearly shown in FIGURES 2 and 3, and these distributor channels are situated adjacent the connection between the conduits 29 and the bearing sleeve 30.

yReferring back to the piston and cylinder assembly 15, each cylinder bore is provided with a piston 38 adapted to reciprocate thereon, piston rings 39 being provided in the conventional manner.

The outer ends 40 of the pistons are bifurcated as at 41 and friction reducing mean-s in the form of rollers 4-2 are supporting for rotation within these bifurcated ends 41, by means `of pins 43.

These rollers are ladapted to engage an inclined thrust plate 44 situated within the casing, said thrust plate being provided with an elongated aperture 45 centrally thereof through which the shaft 2.1 passes freely.

'This thrust plate is pivotally connected by the lower edge 46 thereof to supporting lugs 47 secured to the lower side 48 of the casing. A thrust plate control rod 50 is pivotally connected by the inner end thereof, as at 51, to the upper edge 52 of the thrust plate. This control rod extends exteriorally of the casing and is supported within bearing 53 .within control rod cover plate 54 secured to the upper side of the casing by means of screw bolts 55.

It is necessary to prevent the individual pistons 38 `from rotating within the cylinder bores in order to keep the rollers 42 in the desired position relative to the thrust plate 44 and in this connection I provide a key plate 55 shown in detail in FIGURE 6. This key plate, which is rapertured centrally to permit shaft 21 to pass therethrough, is secured to the end 18 of the block 16 by means of screws 56. This key plate is provided with a plurality of keys 57 extending outwardly of the circumference thereof, one for each cylinder bore 17, these keys just extending over the ends of the cylinder bores as clearly shown in FIGURE 6. Each piston is provided With an elongated key way 58 formed in the wall thereof and extending partway along the length of the piston and the keys 57 engage within the key Ways 58 thus permitting reciprocation of the pistons within the cylinder bores but preventing individual rotation from occurring.

Referring back to the distributor bearing boss 33, the distributor channels 36 and 36A are each connected to la conduit 59 and 60 through drillings 59' and 60', said `conduits being connected to an hydraulic pump 61 driven by a source of power 62. Before describing the control systems desirable for hydraulic motors of this type, the operation of the individual hydraulic motors will Ybe set forth. Hydraulic fluid under pressure is routed from the pump 61 to conduit 59 and thence to distributor channel 36A. It is then conveyed via the conduits 29 to the three cylinders 72 in communication with distributor channel 36A at this time as clearly shown in FIGURE 3. The hydraulic uid under pressure forces the pistons 38 outwardly of their cylinder bores 17 .and due to the engagement of the rollers 42 with the inclined thrust plate 44, the cylinder and piston yassembly 15 revolves. As the uppermost piston vreaches top-deadcenter, it will be noted that the oil supply is cut olf by means of the upper side 37 of the web and as it passes over top-deadcenter and starts to rotate through a furI ther 180 degrees in the direction of arrow 63, the pistons are forced inwardly of their cylinder bores thus exhausting the hydraulic fluid through conduit 60.

It will therefore be appreciated that the hydraulic thrust of the uid is transferred to rotational movement due to the rotation of the cylinder and piston assembly 15 which in turn, of course, is connected to the drive shaft 21.

When the inclined thrust plate 44 is inclined to the maximum extent, the stroke of the individual pistons 38 within the cylinders 17 is at its longest thus giving the lowest speed but that if the inclined plate 44 is moved t0- wards the perpendicular by means of the control shaft 50, the stroke of the individual pistons 38 is shortened thus increasing the speed of rotation of the device.

From the foregoing it will be appreciated that the thrust control plate 44 must be maintained rigidly in its desired position in order to absorb the thrust of the individual pistons 3S as the piston and cylinder assembly 15 rotates and in this connection reference should be made to FIG- URE 9.

I have provided a control piston and cylinder assembly 64, the piston rod 65 of which is pivotally connected to a cross beam 66 mounted upon pivot 67 intermediate the ends thereof. Links 63 are pivotally connected between pivot 67 and the ends of the beam 66 and extend to the aforementioned control rods 50 operating the inclined thrust plate 44. A power assisting valve assembly 69 is provided with actuating lever 70, one end of which is pivotally connected as at 71, to an olf-standing member 72 of the aforementioned beam 66. The other end of the lever 70 extends to a convenient control lever on the steering column of the vehicle (not illustrated). Conduits 73 and 74 extend from the aforementioned pump 61 to the power assisting valve assembly and thence via conduits 73 and 74', to each end of the aforementioned cylinder of the assembly 64.

The power assisting valve assembly is conventional in construction and is similar in operation to the assembly used in automotive power steering. In other words, movement of the lever 70 in the directions of double headed arrow 75, feeds hydraulic fluid from the pump to either side of the piston of the assembly 64 thus actuating the beam 66 and hence the control rods 50 and, what is most important, maintaining the control rods 50 in the desired positions irrespective of the thrust against the control plates 44.

Dealing next to the hydraulic fluid supply to the hydraulic motor, FIGURE 8 shows schematically the basic layout in which the pump 61 is shown with a conduit 76 extending to the casing 10 of the hydraulic motor which, in this embodiment, acts as the oil reservoir 10. A further conduit 77 extends from the pressure side of the pump to a four-way control valve 78 which routes the fluid to conduits 59 or 60, fluid exhausting back through valve 78, to conduit 79 and thence back to the casing 10. By reversing the position of valve 78 of course, the fluid flow through conduits 59 and'60 is reversed thus reversing the rotation of the hydraulic motor.

However it is desirable that various control systems be utilized with the motors in order to provide complete exibility and reference should be made once again to FIGURE 9. Although FIGURE 9 illustrates the use of two hydraulic motors, one for each rear wheel of the vehicle (not illustrated), it will of course be appreciated that it can be utilized for four motors in case a four wheel drive is desired or, a single motor under certain circumstances. In this connection conduits which are similar for both motors have been given similar reference characters.

For the sake of clarification, conduit 59 is referred to as the pressure conduit and conduit 60 as the return conduit.

The return conduits 60 are provided with valves 80 normally maintained in the open position by means of springs 81. These valves are provided to be connected to conventional brake pedals so that by applying pressure to either or both of the brake pedals, the return flow of fluid is restricted thus slowing down the speed of rotation of the particular hydraulic motor which assists in rapid cornering. Also by closing off both valves 80, an emergency stop may be made.

A conduit 82 extendsifrom conduit 77 to a spring ,loaded piston and cylinder assembly 83, the conduit eni closed position by means of spring 89, at which time the piston 85 is fully retracted. However, as soon as pressure from thepump 61 forces fluid through conduit `82, the piston 85 is extended within the cylinder 84 thus opening valve 88 and permitting the deviceto operatein the normal fashion. However, in the event that there is a power failure to the source of power, pressure will drop in conduit 82 thus permitting spring 89 to close valve 88 thus locking the system and preventing loss of control of the vehicle under these circumstances.

When it is desired to stop the vehicle, it is obviously undesirable to closedown the source of power under all circumstances so that I have provided a by-pass valve 90 situated within the exhaust conduit 79 between the fourway valve 78 and the casing 10 of the motor. This bypass valve normally is open so `that fluid can ow from valve 78, through conduit 79 and thence to the casing but a further conduit 91 extends between the valve 90 and the conduit 77 upon the pump side of the four-way valve 78. It will therefore be seen that if the valve 90 is operated to close olf the connection between the four-way valve '78 and the casing `10 and to open conduit ,91to' casing 10, the pump will merely circulate fluid through 91, to the casing, drawing fluid back through the feed conduit 76. This permits the source of power to operate while the vehicle is stationary and at the Sametime, ofcourse,

pressure will be relieved in conduit 82 thus closing valve 88 and locking the hydraulic system in effect `acting as a parking brake.

Means are providedto operate by-pass valve90 and take the form of a lever 92 pivottedupon pin 93 by one end thereof and normally registering against a stop 94.` A link 95 extends intermediate the ends of the lever 9,2, to a bell crank 96 and a further link 97 extends from the other end of bell crank 96 tothe operating lever 90 of the by-pass valve 90. This lever is Vnormally maintained in the non-by-pass condition by means of spring 98.

From a perusal of FIGURE 9 it will be observed that the distal end 99 of the lever 92 is engageable by the end lil() of piston rod 65 of the control piston and cylinder assembly 464 when control rods 50 are in their innermost position, that is, with the motors running at their slowest speed and it is desirable that this` link` 92 be positioned so that it is struck by the end 100 just as the control lever 70 is moved to its closedposition. i

It will therefore be seen that the end 99 of lever 92 will move in the direction of arrow 101 thus, through links 9S and 97 and bell crank 96, operating valve lever 90 moves `in opposition to spring 98 thereby causing the fluid from pump 61 to by-pass as hereinbefore described.

Finally reference should be made to conduit 102 extending between the casing 10 of the two hydraulic motors thus maintaining common level of the fluid within the casings which, as hereinbefore described, act asreservoirs for the hydraulic system.`

Since various modifications can be made in my inve tion as hereinabove described, and many apparently widely different` embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

What I claim as my invention is:

l. An hydraulic motor operated by an hydraulic pump driven by a source of power; said motor comprising in combination an enclosing casing, ends on said casing, a piston and cylinder assembly journalled for rotation within the ends of said casing, a drive shaft secured concen- `trically to one end of said piston and cylinder assembly and extending through one end of said casing, said piston and cylinder assembly comprising a substantially cylindrical cylinder block, a plurality of cylinders formed through said block and concentrically situated therein, a cylinder head on one end of said block, a plurality of pistons reciprocal in said cylinders, an adjustably inclined thrust plate in said casing adjacent the other end of said cylinder block, friction reducing means on the ends of said pistons adjacent said other end of said cylinder block, said friction reducing means contacting said thrust plate,

distributor means in the other end of said casing connected to said hydraulic pump, means connecting said distributor means to said cylinders, and means to control the position of said inclined thrust plate within limits, said means including said thrust plate being pivotally connected by the lower edge thereof to said casing, a control rod pivotally secured to the upper end of said thrust plate and extending exteriorally of said casing, a control piston and cylinder assembly exteriorally of said casing, a power assisting valve assembly adjacent said control piston and cylinder assembly, conduits connecting between said hydraulic pump and said control piston and cylinder assem- Y bly, and said power assisting valve assembly, and linkage operatively connecting said power assisting valve assembly, said control piston and cylinder assembly and said control rod.

2. The device Vaccording to claim 1 which includes a spring loaded cylinder and piston assembly operatively Y connected between said hydraulic pump and said conduits extending through said casing, a valve in one of said last mentioned conduits, said spring loaded cylinder and piston assembly being operatively connected to said valve.

3. The device according to claim l which includes a brake control valve in said conduits extending to said casing.

4. The device according to claim 2 which includes a brake control valve in said conduits extending to said casing.

5. The device according to claim 1 which includes a p by-pass valve inserted between said hydraulic pump and 6. The device according to claim 2 which includes a by-pass valve inserted between said hydraulic pump and said hydraulic motor and linkage means operatively extending between said by-pass valve and said control piston andcylinder assembly whereby when said control piston and cylinder assembly is in an extended position, said by-pass valve is opened and vice versa.

7. The device according to claim 3 which includes a bypass valve inserted between said hydraulic pump and said hydraulic motor and linkage means operatively extending between said by-pass valve and said control piston and cylinder assembly whereby when said control piston and cylinder assembly is in an extended position, said by-pass valve is opened and vice versa.

8. The device according to claim 4 which includes a by-pass valve inserted between said hydraulic pump and said hydraulic motor and linkage means operatively extending between said by-pass valve and said control piston and cylinder assembly whereby when said control piston and cylinder assembly is in an extended position, said by-pass valve is opened and vice versa.

9. The device according to claim l in which said pistons include means to prevent individual rotation thereof when in said cylinders, said means comprising a key plate secured to the drive shaft end of said cylinder block, said key plate having a key extending into the said other end of each of said cylinders, a key way formed partially along the length of each of said pistons and in the Wall thereof, said keys engaging said key ways.

10. The device according to claim 1 in which said distributor means comprises a concentrically positioned, in-

wardly extending bearing boss formed on said one end of V5 said casing, a pair of vertically situated distributor channels formed one on each side of said boss and between the ends thereof, said cylinder head having a concentrically positioned bearing sleeve formed thereon and extending outwardly from said cylinder head and engageable over said bearing boss, a conduit for each of said cylinders extending between said cylinder head at a posi- '8 tion covering each of said cylinders, and said bearing sleeve, each conduit connecting through said cylinder head to the respective cylinder and through the wall of said bearing sleeve, thereby connecting with said distributor channels, and conduits extending between said distributor channels and said hydraulic pump.

References Cited in the le of this patent UNITED STATES PATENTS 10 2,114,076 Golz Apr. 12, 1938 2,468,943 Parsons May 3, 1949 2,478,481 Griffith Aug. 9, 1949 

1. AN HYDRAULIC MOTOR OPERATED BY AN HYDRAULIC PUMP DRIVEN BY A SOURCE OF POWER; SAID MOTOR COMPRISING IN COMBINATION AN ENCLOSING CASING, ENDS SON SAID CASING, A PISTON AND CYLINDER ASSEMBLY JOURNALLED FOR ROTATION WITHIN THE ENDS OF SAID CASING, A DRIVE SHAFT SECURED CONCENTRICALLY TO ONE END OF SAID PISTON AND CYLINDER ASSEMBLY AND EXTENDING THROUGH ONE END OF SAID CASING, SAID PISTON AND CYLINDER ASSEMBLY COMPRISING A SUBSTANTIALLY CYLINDRICAL CYLINDER BLOCK, A PLURALLITY OF CYLINDERS FORMED THROUGH SAID BLOCK AND CONCENTRICALLY SITUATED THEREIN, A CYLINDER HEAD ON ONE END OF SAID BLOCK, A PLURALITY OF PISTONS RECIPROCAL IN SAID CYLINDERS, AN ADJUSTABLY INCLINED THRUST PLATE IN SAID CASING ADJACENT THE OTHER END OF SAID CYLINDER BLOCK, FRICTION REDUCING MEANS ON THE ENDS OF SAID PISTONS ADJACENT SAID OTHER END OF SAID CYLINDER BLOCK, SAID FRICTION REDUCING MEANS CONTACTING SAID THRUST PLATE, DISTRIBUTOR MEANS IN THE OTHER END OF SAID CASING CONNECTED 